The present invention relates to a treatment accessory having a flexible shaft which is slidably inserted in a forceps channel of an endoscope.
Generally, the flexible shaft of a treatment accessory for an endoscope is formed as a closely wound stainless-steel coil. A variety of types of treatment accessories are formed by securing different treating devices, such as forceps or the like, to the distal end of the flexible shaft.
As shown in FIG. 10, when a conventional treatment accessory (in this case), a forceps as a treating device is used to treat an affected part A of human tissue, the distal end of the flexible shaft 91 is extended from a forceps channel 93 of an endoscope 92 straight towards the affected part A. In this example, since the affected part A is not directly in front of the treatment accessory, it is difficult to treat the affected part A accurately.
In this case, it may be necessary to press contact the distal end of the treatment accessory, i.e., attempt to hook the treatment accessory onto the tissue in the neighborhood of the affected part A, and then further extend the flexible shaft 91 from the forceps channel 93, such that the flexible shaft 91 is bent and the orientation of the distal end of the treatment accessory is changed. However, since the flexible shaft 91 of the treatment accessory is a closely wound coil having a relatively strong elasticity, the distal end of the treatment accessory may slip off the portion at which it has been press contacted or hooked. If the distal end slips, the flexible shaft 91 elastically straightens back to the position shown in FIG. 10.
In order to overcome the above problem, treatment accessories having a flexible shaft which is remotely controlled to bend in a desired direction are known. Examples of such an instrument are disclosed in Japanese Utility Model Registration Publication SHO 52-22146, Japan Utility Model Provisional Publication HEI 1-119621, and the like.
In such an instrument, however, a manipulation portion of the endoscope must include mechanisms for simultaneously performing the bending operation and the treatment of the affected portion A. Such a device is difficult for a user to operate since the positioning of the distal end of the treatment accessory in front of the affected part is difficult. Further, in such an instrument, both an operation wire for the operation of the treating device of the affected part and another operation wire for the bending of the flexible shaft are enclosed within the flexible shaft. As such, the flexible shaft must be larger and more rigid, making it more difficult to insert the flexible shaft in the forceps channel of the endoscope and then bend the flexible shaft at the appropriate position.
In a particular case, the treating device may be a cutting or grasping device that opens and closes, such as a biopsy forceps, a grasping forceps or the like, which includes a plurality of members that are openable about a fulcrum to be used for collecting or grasping material, such as mucous or the like, inside a living body. In this case, generally, the end of such a treating device is formed to be substantially spherical in a closed state so that the device can be inserted in channels within the body easily, and in order to prevent the device from damaging the inner wall of the body.
A conventional treating device generally has a shape as shown in FIG. 34. The conventional treating device includes two cups 94 that can be opened and closed. When such a conventional treating device is pressed against an affected part A from other than a vertical direction, for example, diagonally as shown in FIG. 34, the spherical surface of the cup 94 may slip on the tissue surface, such that the material in the affected portion A cannot be collected easily.
In order to overcome the problem of slipping, a treatment device, as disclosed in Japanese Utility Model Publication-SHO 56-40424, and as shown in example form in FIG. 35, may be provided with cups 94' having an extended end portion 95. With this arrangement of a treating device, the extended end portion 95 catches on and enters into the tissue such that the cup 94' does not slip and the position of the treatment device may be more easily adjusted with respect to the affected part A.
However, as shown in FIG. 35, the provision of the extended end portion 95 may cause a problem in that, when the opened cups 94' are closed, the tissue surface is pushed away from the cups 94' such that it is difficult to collect a large amount of material.